Synthesis of phthalazine quinone derivatives and evaluation on their cytotoxic activity

Abstract

질소를 포함한 헤테로 고리 화합물 유도체들은 항암활성이 우수한 것으로 규명되어 이에 대한 연구가 활발히 진행되어 왔다. 본 연구에서는 출발물질인 6,7-dichloro-5,8-phthalazinedione (12)에 고리를 증가시켜 새로운 화합물들을 합성했으며 이들은 평면의 3~4환의 quinone 모핵을 갖는 DNA-intercalator로서 항암활성이 높을 것으로 기대된다. 화합물 12를 여러 종류의 방향족 아민과 반응시켜 6-arylamino-7-chloro-5,8-phthalazinediones (AI) 유도체를 합성하였으며 이들을 DMF를 용매로 하여 sodium azide와 반응시켜 6,11-dihydro-quinoxalino[2,3-b]phthalazine-6,11-dione(A) 유도체를 얻었다. 또한 2-methyl-4,9-dihydro-1H-imidazo[4,5-g]phthalazine-4,9-dione (B) 유도체와 7,8,9,10-tetrahydro-pyridino[1',2':2,3]imidazo[4,5-g]phthalazine-5,12-dione (C)유도체를 합성하였다. 6,7-Dichloroquinoline-5,8-dione 8 또는 화합물 12를 여러 종류의 2-aminopyridine유도체와 반응시켜 ortho-quinone을 모핵으로 하는 4a,10,11-triaza- 와 4a,10,11-tetra-azabenzo[3,2-a]fluorene-5,6-diones (D) 화합물들을 얻었다. 또한 화합물 D와 KOH를 반응시켜 두 개의 carboxyl 기를 갖는 화합물 EI를 합성하였다. 이와 같이 합성된 화합물들의 세포 독성 효능을 SRB assay로 측정하였으며 현재 항암제로 사용중인 doxorubicin, etoposide, ellipticine과 활성을 비교하였다. 대부분의 화합물들은 tumor cell line 모두에서 ellipticine보다 더 좋은 세포 독성 효과를 나타내었으며, 또한 신규로 합성된 많은 화합물들이 doxorubicin과 비슷하거나 우수한 활성을 나타내었다. 일반적으로 고리의 수가 증가할수록 더 우수한 활성을 나타내는 결과를 얻었다. 또한 합성된 화합물들의 항암활성 기전을 조사해보기 위해서 DNA relaxation과 DNA decatenation assay를 통하여 이들 화합물에 대한 topoisomerase I 혹은 II 활성저해 효과를 측정하였다. 그러나 이들 화합물들은 우수한 항암활성을 보여주었지만, topoisomerase I 혹은 II 활성 저해 효과는 매우 낮았다.;Based on the cytotoxic potential of the heterocyclic quinones, more heterocyclic rings were annulated to 6,7-dichloro-5,8-phthalazinedione 12 for the synthesis of new compounds with a planar tri- or tetracyclic quinone moiety, which were expected to enhance cytotoxicity in the human cancer cell lines as a DNA-intercalator. 6,7-Dichloro-5,8-phthalazinedione 12 was reacted with various arylamines to give the 6-arylamino-7-chloro-5,8-phthalazinediones AI. A series of 6,11-dihydro-quinoxalino[2,3-b]phthalazine-6,11-dione A were synthesized by reacting AI with sodium azide in N,N-dimethylformamide (DMF). The 2-methyl-4,9-dihydro-1-substituted-1H-imidazo[4,5-g]phthalazine-4,9-dione derivatives B and 7,8,9,10-tetrahydro-pyridino[1',2':2,3]imidazo[4,5-g]phthalazine-5,12-dione derivatives C were synthesized. 6,7-Dichloroquinoline-5,8-dione 8 and 6,7-dichloro-5,8-phthalazine-dione 12 were reacted with various 2-aminopyridine derivatives to afford ortho-quinone derivatives, 4a,10,11-triaza- and 4a,10,11-tetra-azabenzo[3,2-a]fluorene-5,6-diones D, respectively. The reaction of compound D with KOH in n-butanol resulted in cleavage between the two carbonyl bond to give compound EI which has two carboxyl groups. The prepared compounds A, B, and D were evaluated for their cytotoxic activity in vitro using SRB(Sulforhodamine B) assay, against the human cancer cell lines and their activities were compared with clinically available anticancer agents, doxorubicin, etoposide and ellipticine. Almost all the compounds exhibited greater cytotoxic activities upon the growth of a variety of human cancer cell lines than etoposide and some compounds showed cytotoxicity superior or comparable to doxorubicin. In addition, based on the intercalating effects of heterocyclic quinones to DNA, we investigated whether the cytotoxicity of quinoxalinophthalazine-6,11-diones A and imidazophthalazine-4,9-diones B was related to the topoisomerase activity. Although compounds A and B exhibited excellent cytotoxicity, the inhibitory activity against topoisomerase I or II was quite weak.